Resonant all-electric spin pumping with spin-orbit coupling

All-electric devices for the generation and filtering of spin currents are of crucial importance for spintronics experiments and applications. Here we consider a quantum dot between two metallic leads in the presence of spin-orbit coupling, and we analyze in the frame of a scattering matrix approach the conditions for generating spin currents in an adiabatically driven two-terminal device. We then focus on a dot with two resonant orbitals and show by specific examples that both spin filtering and pure spin current generation can be achieved. Finally, we discuss the effect of the Coulomb interaction.